Sure, but I don't think they must be mutually exclusive; on the contrary: in the late stages when your character is a tank, swarms of minions that posed a challenge in early stages become just a nuisance, mostly. You are walking legend slaying dragons for breakfast, everybody and their dog knows about your invincibility … but instead of giving you some respect, they try to bite your heels on the first sight. I guess the "fun aspect" of seeing them flee and not restraining your movement at all could be slightly more satisfying than taking them down in a single hit one-by-one for the thousand time.

I think games don’t have to be fun. There’s plenty of games where fun would be super inappropriate and yet the games are very popular. This applies to a lot of psychological or survival horror games. I think better is that a game must be compelling. There must be something encouraging you to play more, more so than any frustration or conflict the game introduces.

You definitely don't want too much realism, for most games - you probably don't want to manage bathroom trips! We just assume it happens "off camera"

But when humanoid enemies behave in plainly stupid ways it's a real immersion-breaker for me. I've been gaming a looooong time, so I'm quite adept at the necessary mental gymnastics to enjoy stuff anyway... but... still... games could be better here. (And by "better" I mean "more fun")